LCL型级联H桥STATCOM阻抗重塑谐振抑制策略

LCL-type Cascaded H-bridge STATCOM Impedance Remodeling Resonance Suppression Strategy

针对电力系统缺乏无功导致电压跌落的问题,通常采用静止无功发生装置(STATCOM)对电网无功综合补偿,而级联H桥STATCOM以易模块化、谐波含量小等特点广泛应用于电力系统无功补偿中,且使用过程中通常搭配LCL滤波器消除高频谐波。为应对级联H桥STATCOM并网过程中与LCL滤波器交互引起的高频谐振,此处提出一种阻抗重塑方法,针对级联H桥STATCOM与LCL滤波器交互的高频谐振机理建立序阻抗模型,并制定了基于序阻抗模型的阻抗重塑控制策略,有效抑制了高频谐振,并基于5 kvar样机试验验证了阻抗模型的正确性及阻抗重塑策略的有效性。

For the problem of lack of reactive power in the power system resulting in voltage dips,the static reactive power generation(STATCOM)is usually used to compensate the grid reactive power comprehensively,the cascaded Hbridge STATCOM is widely used in power system reactive power compensation with easy modularity and small harmonic content,and is usually used with LCL filters to eliminate high frequency harmonics.In order to cope with the high frequency resonance caused by the interaction between cascaded H-bridge STATCOM and LCL filter in the process of grid connection,an impedance reshaping method is proposed,the sequential impedance model is established for the high frequency resonance mechanism of the interaction between cascaded H-bridge STATCOM and LCL filter,and an impedance reshaping control strategy based on the sequential impedance model is developed,which effectively suppresses the high frequency resonance,and based on the 5 kvar prototype test,the correctness of the impedance model and the effectiveness of the impedance reshaping strategy are verified.